The present invention relates to earth removing equipment and more particularly to such equipment utilized for excavating material along a "face" or upright planar earth surface of an area to be excavated.
It has long been desirable to provide earth excavating equipment that will effectively remove ore deposits or other earthen material from an upright face. It is also desirable to obtain some form of apparatus that will remove material in successive layers from a face while simultaneously moving the separated material to a remote location.
U.S. Pat. No. 2,689,717, granted to F. Bainbridge, on Sept. 21, 1954, discloses a plow-mining method and apparatus. In this particular apparatus, a double-edged cutting blade is utilized to remove material from a vertical face while traveling backwardly or forwardly along a framework aligned parallel to the face. Opposite ends of the framework are movably mounted to tracks that enable incremental movement of the apparatus towards the face after each successive cut. The cutting edge of the blade assembly extends from the top to the bottom edge of the face. It includes a vibrating assembly that is operatively connected to the forward cutting edges of the blades to facilitate a smooth passage of the blades through the earth engaged therewith. The blades are moved by cables that are attached to the blade carrying carriage.
U.S. Pat. No. 3,245,722, to F. H. Creules, et al., issued Apr. 12, 1966, discloses a mining face conveyor in which a double-edged cutting blade assembly is moved along the length of a face in order to remove successive layers of materials from the face and deposit such material unto a conveyor that is oriented parallel to the face. The cutting assembly is specifically designed so a leading cutting edge will dig into the face while the following or rearward cutting edge is held clear of the face. When the blade assembly is moved in the opposite direction, the assembly is pivoted so the other assemblies engage the face and above mentioned assembly is pivoted clear of the face. Cutting edges of the blade assembly produce a face that is relatively upright by nature, but has an upper portion that is indented further than a lower face portion. The cutting operation is performed by two separate blade portions. A forward blade portion removes the bottom part of the layer while rearward blade portion removes the indented upper part of the face. U.S. Pat. No. 2,539,962 to J. B. Mavor, issued Jan. 30, 1951, discloses a mining machine that includes a blade assembly in which the shearing components are longitudinally movable relative to each other. In operation, on of the components advances longitudinally while the other is held stationary. Once the one element if fully extended, it is held stationary while the remaining element is advanced to overtake the first element. Thus, an "inch-worm" effect is produced by the alternately movable slicing components.
U.S. Pat. No. 3,530,599 granted to F. H. Holland, on Sept. 29, 1970, discloses an elevating belt loader and excavation apparatus. This assembly also makes use of shearing blades to cut successive layers from an upright face. Two distinct blades are utilized to cut a step-shaped formation as the blade assembly moves longitudinally along the face. An upright blade makes a vertical cut line along the face while, at the same time, a horizontal blade makes a horizontal cut that is outboard in relation to the vertical cut. The material from both blades is directed onto a lateral conveyor to be moved from the area of the face laterally outward to a discharge end and into a receiving truck or other means of transportation.
Another excavating device is shown by M. E. Lasher in U.S. Pat. No. 150,767, patented May 12, 1874. This device, instead of using two separate slicing elements, uses a plow share and mold board. This unit is utilized by the device to shear off successive layers of material and direct it onto a lateral conveyor.
A horizontal blade in an excavation device is described in U.S. Pat. No. 11,382, granted to J. Lyon and issued July 25, 1854. This device uses a substantially horizontal blade that is inclined upward in a rearward direction to a lateral discharge conveyor. As the device is pulled in a forward direction a horizontal blade engages the earth and lifts a layer thereof upwardly along the inclined plane and finally onto the lateral discharge conveyor.
U.S. Pat. No. 2,386,187 to R. Q. Armington et al issued Oct. 9, 1945, also discloses a scoop-type excavator that is somewhat similar to the Lyon device only having a discharge conveyor that forms an acute angle at the forward direction of travel rather than a perpendicular angle as disclosed by Lyons.
Other scooping and associated conveying apparatus are disclosed in U.S. Pat. Nos. 3,245,159; 3,885,332; 3,778,912; 3,470,634; and 839,516.
Nearly all the above cited and disclosed patents operate on the principle of the ordinary plow share and mold board that is disclosed in U.S. Pat. No. 150,767, granted in 1874, wherein a basically wedge shaped ground breaking element is utilized. This element may be basically described in two components -- one being a lower cutting element that protrudes forwardly and below an upward and rearward second element. The two elements are joined by a smooth curved surface designed to direct material (disengaged by the leading lower element) upwardly and to one side of the upward element. The difficulty here arises from the fact that the lower end must be pushed or pulled through the earth and therefore bear the burden of the entire depth of the cut; whereas, if the upper part preceded the lower part, the upper portions of the cut could be removed before the lower portion becomes engaged with the lower cutting edge. Therefore, less weight and drag would be sustained by the cutting elements when in operation as opposed to the older lower leading edge types.